Spatial patterns in assemblage structures of pelagic forage fish and zooplankton in western Lake Superior

Journal of Great Lakes Research
By: , and 

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Abstract

We assessed abundance, size, and species composition of forage fish and zooplankton communities of western Lake Superior during August 1996 and July 1997. Data were analyzed for three ecoregions (Duluth-Superior, Apostle Islands, and the open lake) differing in bathymetry and limnological and biological patterns. Zooplankton abundance was three times higher in the Duluth-Superior and Apostle Islands regions than in the open lake due to the large numbers of rotifers. Copepods were far more abundant than Cladocera in all ecoregions. Mean zooplankton size was larger in the open lake due to dominance by large calanoid copepods although size of individual taxa was similar among ecoregions. Forage fish abundance and biomass was highest in the Apostle Islands region and lowest in the open lake ecoregion. Lake herring (Coregonus artedi), rainbow smelt (Osmerus mordax) and deepwater ciscoes (Coregonus spp.) comprised over 90% of the abundance and biomass of fishes caught in midwater trawls and recorded with hydroacoustics. Growth and condition of fish was good, suggesting they were not resource limited. Fish and zooplankton assemblages differed among the three ecoregions of western Lake Superior, due to a combination of physical and limnological factors related to bathymetry and landscape position.

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Publication type Article
Publication Subtype Journal Article
Title Spatial patterns in assemblage structures of pelagic forage fish and zooplankton in western Lake Superior
Series title Journal of Great Lakes Research
DOI 10.1016/S0380-1330(04)70400-1
Volume 30
Year Published 2004
Language English
Publisher Elsevier
Contributing office(s) Great Lakes Science Center
Description 12 p.
First page 395
Last page 406
Country United States
State Michigan, Minnesota, Wisconsin
Other Geospatial Lake Superior
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